The present invention relates generally to pipe loading devices. More particularly, the present invention relates to pipe loading devices for use with directional drilling machines.
Directional drilling machines are used to drill holes along a generally horizontal path beneath the ground. After a hole is drilled, a length of cable or the like can be passed through the hole. Such directional drilling machines eliminate the need for digging a long trench to lay a length of cable or the like.
A typical directional drilling machine includes an elongated track that can be aligned at an inclined orientation relative to the ground. A drive head is mounted on the track so as to be moveable along the length of the track. The drive head includes a drive member that is rotated about a drive axis that is generally parallel to the track. The drive member is adapted for connection to a length of pipe. For example, the drive member can include a threaded end having either female or male threads.
To drill a hole using the directional drilling machine, the track is oriented at an inclined angle relative to the ground, and the drive head is retracted to an upper end of the track. Next, a length of pipe is unloaded from a magazine and is coupled to the drive member of the drive head. Once the pipe is connected to the drive head, the drive head is driven in a downward direction along the inclined track. As the drive head is driven downward, the drive member is concurrently rotated about the drive axis. Typically, a cutting element is mounted at the distal end of the pipe. Consequently, as the drive head is driven down the track, the rotating pipe is pushed into the ground thereby causing the pipe to drill or bore a hole. By stringing multiple pipes together, it is possible to drill holes having relatively long lengths.
After drilling a hole, it is common for a back reamer to be connected to the end of the drill string. Once the back reamer is connected to the end of the drill string, the directional drilling apparatus is used to pull the string of pipes back toward the drilling machine. As the string of pipes is pulled back toward the drilling machine, the reamer enlarges the pre-drilled hole, and the pipes are individually uncoupled from the drill string and loaded back into the magazine of the directional drilling machine.
To enhance drilling productivity, it is important to maximize the efficiency in which pipes can be loaded into and unloaded from the magazine of a directional drilling machine. Until fairly recently, pipes were manually carried between the magazine and the drive head of a drilling machine, and were also manually loaded into and unloaded from the magazine. Recent developments have improved pipe loading and unloading efficiencies through automation. For example, U.S. Pat. No. 5,556,253 to Rozendaal et al. (the ""253 patent), and U.S. Pat. No. 5,607,280 (the ""280 patent) to Rozendaal, disclose improved pipe loading/unloading devices. The ""253 and ""280 patents disclose devices that effectively use gravity to automatically unload pipes from a magazine. The ""253 and ""280 patents also disclose devices each having pipe transfer members that automatically move pipes between a magazine and a drive head. The advances provided by the devices disclosed in the ""253 and ""280 patents have assisted in significantly improving a drill operator""s ability to enhance drilling productivity.
One aspect of the present invention relates to a drilling apparatus including a magazine for holding a plurality of pipes, and a drive head having a drive member adapted to be coupled to a pipe. The drive member is aligned along a drive axis. The drilling apparatus also includes a first drive mechanism for rotating the drive member about the drive axis, and a second drive mechanism for moving the drive member axially along the drive axis. The drilling apparatus is provided with a pipe transfer member for transferring pipes between the magazine and the drive head. The pipe transfer member defines a pipe receiving region for receiving or holding a pipe. The pipe transfer member is movable between a first orientation in which the pipe receiving region is positioned adjacent to the magazine, and a second orientation in which the pipe receiving region is positioned adjacent to the drive axis of the drive head. The drilling apparatus further includes a magnet for magnetically attracting a pipe received within the pipe receiving region of the pipe transfer member at least when the pipe transfer member is in the second orientation. The magnet is adapted to magnetically hold the pipe in coaxial alignment with the drive axis while the drive member of the drive head is being coupled to the pipe or uncoupled from the pipe.
Another aspect of the present invention relates to a drilling apparatus including a magazine for holding a plurality of pipes, and a drive head having a drive member adapted to be coupled to a pipe. The drive member is aligned along a drive axis and is rotated about the drive axis by a first drive mechanism. A second drive mechanism is provided for moving the drive member axially along the drive axis. The drilling apparatus also includes a pipe transfer member for transferring pipes between the magazine and the drive head. The pipe transfer member defines a pipe receiving region for receiving a pipe. The pipe transfer member is movable between a first orientation in which the pipe receiving region is located adjacent to the magazine, and a second orientation in which the pipe receiving region is located adjacent to the drive axis of the drive head. The drilling apparatus further includes a holding means for attracting a pipe received within the pipe receiving region of the pipe transfer member toward a gripping surface at least when the pipe transfer member is in the second orientation. The holding means is adapted to hold the pipe against the gripping surface such that the pipe is held in coaxial alignment with the drive axis while the drive member of the drive head is being coupled to the pipe or uncoupled from the pipe.
A further aspect of the present invention relates to a method for coupling a pipe to a drilling apparatus. The drilling apparatus includes a drive head having a drive member adapted to be coupled to a pipe. A first drive mechanism rotates the drive member about the drive axis, while a second mechanism axially moves the drive head along the drive axis. The method includes moving the pipe into coaxial alignment with the drive axis, and magnetically attracting the pipe against a magnetic gripping surface to hold the pipe in coaxial alignment with the drive axis. The pipe is then coupled to the drive member while the pipe is magnetically held in coaxial alignment with the drive axis.
Still another aspect of the present invention relates to a method for loading a magazine of a drilling apparatus. The drilling apparatus includes a drive head having a drive member coupled to a pipe. The drilling apparatus also includes a first drive mechanism for rotating the drive member about a drive axis, and a second drive mechanism for moving the drive head axially along the drive axis. The method includes providing a pipe transfer member having a pipe receiving region, and moving the pipe transfer member such that the pipe coupled to the drive member is received at the pipe receiving region. The method also includes uncoupling the pipe from the drive member, and magnetically attracting the uncoupled pipe against a magnetic gripping surface to hold the pipe at the pipe receiving region. The method further includes moving the pipe transfer member such that the uncoupled pipe is conveyed to a magazine, and loading the uncoupled pipe into the magazine.
A variety of advantages of the invention will be set forth in part in the description that follows, and in part will be apparent from the description, or may be learned by practicing the invention. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.